This invention relates to an aqueous dispersion of an olefin copolymer. These dispersions may be film-forming at room temperature and can have excellent physical and mechanical properties.
Aqueous dispersions of polyolefins are known in the art, although none are reported to have been derived from polyolefins having molecular weights above 40,000. For example, in U.S. Pat. No. 3,734,686, incorporated herein by reference, Douglas et al., discloses a mechanically stable aqueous emulsion of polyethylene particles having an average molecular weight ranging from about 7,000 to 40,000. These dispersions are taught to be useful for treating carpets.
In U.S. Pat. No. 3,418,265, McClain teaches that aqueous film-forming ethylene polymer latexes containing ethylene polymer particles of submicron size can be prepared by dispersing in water an ethylene polymer and a water-soluble block copolymer of ethylene oxide and propylene oxide. No examples of stable dispersions of ethylene polymers having a molecular weight above 27,000 are reported.
Many of the polyolefin latexes previously described are actually not purely polyolefinic, but rather contain polar groups, such as acids or halides. Since the film-forming properties of these so-called polyolefin latexes are often adversely influenced by the presence of these polar substituents, it would be desirable to prepare latexes derived from higher molecular weight polyethylenes that did not contain polar groups. It would be of further value if these latexes were film-forming at room temperatures.